Mechanistic Details of Nickel(0)-Assisted Oxidative Coupling of CO 2 with C 2 H 4

The mechanism of the experimentally observed formation of the five-membered nickela−carboxylate complex in the nickel(0)-assisted oxidative coupling of CO 2 and C 2 H 4 is revealed by means of density functional calculations. The reliability of the applied DFT methodology has been first assessed by comparison to high-level coupled-cluster calculations on a relevant model reaction. The most important stationary points on the potential energy surface associated with the title reaction have been located, and low-energy reaction pathways have been identified. We show that the C−C bond formation occurs in a single step by the reaction of a nickel−ethylene complex with an incoming CO 2 molecule. The solvent effect and the influence of the ancillary ligands on the reaction energetics are examined, and both are shown to be important in these reactions.